The announcement follows news that one of the teen victims of an alleged sexual assault at a Labour summer camp has contacted police.

Labour Party general secretary Andrew Kirton confirmed the development this morning.

It is alleged a 20-year-old man sexually assaulted four teenagers, all aged 16, including putting his hands down the pants of at least three of them at the Young Labour summer camp in Waihi last month.

Kirton said he was told yesterday by one of the victims' families that the teen had now contacted police.

He also addressed speculation that the 20-year-old culprit at the summer camp is the son of a Labour minister.

Kirton said while he did not know all the 20-year-old 's family links, "I'm certain that's not the case."

A spokesman for Prime Minister Jacinda Ardern said he did not believe that was accurate.

Kirton has defended the way Labour has handled the allegations of sexual misconduct at party functions, and says he will not resign.

A second allegation has emerged as the party battles criticism for the way it handled a case last month in which three 16-year-olds were indecently assaulted at a summer school by a drunken 20-year-old.

Kirton told Mike Hosking this morning that the second incident took place at another event and not at the summer school for Young Labour.

"It was at a Labour Party event, I don't want to go into too much detail about the event out of respect for the individual," Kirton said.

He said the alleged victim, who is in the 20s, was offered support by the party, including support of going to the police. Whether the cases ended up with the police or not were up to them, Kirton said.

Kirton acknowledged the party could have done better in handling the cases, and in bringing professional help earlier.

When pressed by Hosking, Kirton defended why the party did not inform the parents of those involved - but only went to professionals.

Hosking said: "You clearly aren't a parent of teenagers are you? Let me tell you as a parent of two teenagers that what you're doing is wrong, what you did is wrong, going to professionals is wrong, giving kids the rights they don't have is wrong. You go to the parents... why don't you get that?"

Kirton said the decision to not inform parents was so that the teenagers, who are 16 to 18, "could make decisions that they thought were appropriate".

"When we talked to experts who are professionals in this field, that is the advice that they feel is the right course of action," Kirton said.

He said the party was reviewing what it's done, with professional help "to make sure we're displaying best practice in these circumstances".

Kirton did not inform Prime Minister Jacinda Ardern about the allegations - she found out from a journalist. But he has kept her office informed in the case of the latest allegation.

When asked if he would quit, Kirton responded: "No."

Former Act and National leader Don Brash criticised the level of media coverage saying it was being overplayed in light of other world news.

"Any kind of sexual harassment is wrong and I don't want to diminish that. I was just irritated that literally every news bulletin I listened to between 9am and noon, the first item was about this particular issue. To make this the primary news item for days on end seems to me to be overplaying it."

He said there was the developing situation between Russia and the United Kingdom over the use of nerve agent in Britain, US Secretary of State Rex Tillerson has been fired, and North Korea and US President Donald Trump were supposed to be meeting.

He could the issue was "absolutely embarrassing" for the Labour Party.

"If you're running a camp for your young supporters, many of who are teenagers, the basic first rule is to keep them safe. In this case, they clearly failed in that. I'm not saying this is a trivial matter. I'm just saying it isn't World War III."

He said the alleged actions of the 20-year-old in putting his hands down the pants of at least three 16-18 year olds were serious but should not be conflated with something such as rape.

"Any sexual harassment is bad, but they're not equally bad. The difference between that and a violent rape, which leaves someone bleeding and battered, they're two different gradations. And I think we devalue the language by pretending they're equally bad."

Timeline of events

• February 9: Prime Minister Jacinda Ardern speaks at the opening of Young Labour's "Summer School" camp in Waihi.

• February 10: A 20-year-old man allegedly sexually harasses or assaults four 16-year-olds - two males and two females - during a camp event.

• February 11: The man is thrown out and the victims offered support. Shortly after Labour's general secretary Andrew Kirton is informed.

• March 3: Follow-up offer of professional help offered to victims, according to Kirton.

• March 4: Energy Minister Megan Woods receives complaint about lack of response by Young Labour and contacts Kirton, who says the matter is being dealt with "appropriately". Woods does not raise with Ardern or anyone else.

• March 12: Newsroom publishes the allegations and Ardern is blindsided by media questions. The party issues a statement saying it is "extremely disappointed" about the incident and launches a review.

• March 13: Ardern accepts the party was too slow to offer support but says she won't sack Kirton, who later reveals he's been told a second incident at another camp years earlier.